New Zealand Empirical Erosion Model (NZeem®)


NZeem® is an empirical model that predicts mean annual sediment yield from a given catchment, based on annual rainfall, type of terrain and percentage of woody vegetation cover.


NZeem® partitions the New Zealand landscape according to the factors controlling erosion: rock type, land form (especially slope angle), rainfall and land cover. The erosion co‑efficient (a) is a measure of inherent erosion susceptibility related to land-form characteristics (geology, slope angle, etc). The rock type and land-form data comes from the NZ Land Resource Inventory.

 The model is calibrated on about 200 sediment yield data sets from most regions in New Zealand. NZeem® is claimed to be applicable to all types and sizes of catchments (Dymond et al, 2010). It also builds on earlier work resulting in a database and digital map of mean specific sediment yield (kg / km2 / yr) produced by NIWA and Landcare Research as part of a project funded by the Foundation for Research Science and Technology for studying carbon transfers associated with erosion (Hicks et al, 2003).

Latest Version 1
State of Development Released and updated

Development Contact

John Dymond
+64 6 353 4800
Landcare Research
Private Bag 11052
Manawatu Mail Centre
Palmerston North 4442,
New Zealand

Main Developers

  • Landcare Research


Outcome Areas Environmental
Management Domains Land, Natural Hazards
Intended End Users Researchers, local and regional councils
Spatial Resolutions 10-100m
Spatial Extents Local (i.e. Catchment or District), Regional, National
Spatial Dimensions 2D
Temporal Resolutions Years
Temporal Extents Decades
Steady State or Dynamic Dynamic
Level of Integration Environmental

Input & Output Data

Key Input Data Land Use, Land Cover, Rainfall Geology and soil types
Input Data Formats Raster GIS
Key Output Data Erosion rate
Output Data Formats Raster GIS


Open/Closed Source Closed Source
Licence Type Data licence required
Licence Cost
(Non Commercial)
Licence Cost
Licence Purchase Contact
John Dymond
+64 6 353 4800
Landcare Research
Private Bag 11052
Manawatu Mail Centre
Palmerston North 4442,
New Zealand

User Information

Operating Systems MS Windows, Mac OS X, Linux, Dos executable
Software Needed Internet Browser
User Interface Please Select Web page
Ease of Use Easy Just clicking in a web browser.
Use in Policy Process Plan (Policy Formulation), Do (Policy Implementation)
Support Contact John Dymond for any questions.
Users Forum None

Technical Considerations

Programming Language Two deployments: (1) Python+RIOS or (2) Imagine Spatial Modeller
Methods included for calibration and validation Measurements of sediment yield in rivers to validate.
Methods included for managing uncertainty Uncertainty has been assesed but is not part of the webpage
Analytical Techniques GIS
Model Structure

This is in the manual

Keywords erosion, sediment, rivers, farm plans, soil conservation
Linkages to other Models

Requires input from the Landcare Research's highly erodible land model.

Key References

Dymond JR, Betts HD, Schierlitz CS (2010). An erosion model for evaluating land-use scenarios in New Zealand. Environmental Modelling and Software 25: 289-298

Dymond JR, Shepherd JD 2006. Highly erodible land in the Manawatu-Wanganui Region. Landcare Research Contract Report LC0607/027 to MAF Policy.

Dymond J, Shepherd J and Page M 2008. Roll out of erosion models for Regional Councils. Landcare Research Contract Report LC0708/094

Barry, L. et al. 2011 Valuing Avoided Soil Erosion by Considering Private and Public Net Benefits. Paper at NZARES Conference 

Associated Case Studies

NZeem - Waikato River Suspended Sediment

The Waikato Regional Council (WRC) Healthy Rivers: Plan for Change/Wai Ora: He Rautaki Whakapaipai aims to reduce inputs of sediment, bacteria and nutrients (primarily nitrogen and phosphorus) to water bodies (including groundwater) in the Waikato and Waipa River catchments.


NZeem - Erosion carbon study

Soil erosion in New Zealand exports much sediment and particulate organic carbon (POC) to the sea.


Other Key Case Studies

Assessing erosion in the Waipa catchment using the New Zealand Empirical Erosion Model (NZeem®), Highly Erodible Land (HEL), and SedNetNZ models - WRC Technical Report TR201354